Whistleblower vs. Leaker?

I received an email from a reader that raises some interesting questions in response to this article in the Washington Post. The story concerns the court case of former NSA executive Thomas A. Drake.

Here’s the content of the email:

I’d be interested in anyone’s thoughts on this story, the former NSA manager being tried under the Espionage Act for leaking information on NSA mismanagement to the Baltimore Sun. There was a good New Yorker article on it recently too. I’m usually all for prosecuting people who leak sensitive information, but in this case the information involves contractor issues and wasted resources, so would seem to be whistleblowing. As a former consultant with the IC, I know there are a lot of issues with contractors and poorly-implemented programs, so this information needs to get out somehow. At the same time, incidents like the State Department cable leaks are incredibly disruptive, so the distinction between good leak and bad leak might be hard to make.

Any thoughts from readers? For anyone with a legal background in this sort of thing, how do we know where whistleblowing ends and leaking starts? For political scientists who have studied this sort of thing, is there an accepted way to categorize incidents of whistleblowing as opposed to leaking?